Miley Cyrus may have announced her release from the hospital days ago, but the singer has had to cancel more tour dates as a result of a serious allergic reaction.

Cyrus, the 21-year-old singer who has been performing on her "Bangerz" tour, was initially hospitalized due to an allergic reaction to the medicine Cephalexin. The singer was prescribed the drug after suffering from a sinus infection, according to E! News.

While she thought she was in the clear on the road to recovery, it seems Cyrus has suffered another setback.

"Cyrus is continuing to recover from the severe allergic reaction she suffered on April 15. After a period of improvement, Cyrus' symptoms have returned and Doctor's will not permit her to travel," a statement from the singer's representatives obtained by E! reads. "Cyrus must remain under Doctor's care at this time. The London date at O2 Arena will proceed as planned on May 6th."

This means that Cyrus was forced to cancel a few dates scheduled for the European leg of her "Bangerz" tour.

After being released from the hospital following an extended stay, Cyrus spoke to KIIS FM's radio host Ryan Seacrest about her scary experience.

"It was so scary," Cyrus told Seacrest Monday. "When you're allergic to something, you're literally poisoning yourself, so I had just been poisoning myself for a week with something I didn't know I was really, scary allergic to."

The singer admitted that it was tough to follow doctors orders instead of tour.

"Being on the road, especially me, I'm not someone that wants to lay down and actually get 100 percent better, It was like every two or three hours I would be OK, and then all of the sudden it would happen to me again," she told Seacrest. "It was insane. I was begging the doctors, 'Let me out just to do the show,' but there was basically no way."